The present invention relates to a vehicle tire having an improved tread portion capable of improving wet performance without sacrificing wear resistance.
Vehicle tires such as pneumatic tires for passenger cars, light trucks and the like are usually provided with circumferentially extending main grooves and lateral grooves to provide a good wet performance.
If the grooved area is increased, drainage from the ground contacting patch is increased and wet performance may be improved. But, wear resistance, uneven wear resistance tend to decrease.
It is therefore, an object of the present invention to provide a vehicle tire in which wet performance can be improved without sacrificing wear resistance.
According to the present invention, a vehicle tire has a tread portion comprising
circumferentially extending straight main grooves including a central main groove on the tire equator and an axially outer main groove on each side thereof,
lug grooves extending from the axially outer main grooves towards the central main groove, but terminating before the central main groove,
each of the lug grooves comprising a first curved portion, a second curved portion and a straight portion arranged in this order from the outer main groove towards the central main groove, wherein a width of the first curved portion is in the range of from 60 to 80% of the width of the outer main groove, a width of the second curved portion is not less than 25% but less than 60% of the width of the outer main groove, and a width of the straight portion is not more than 25% of the width of the outer main groove,
an inclination angle of each lug groove with respect to the tire circumferential direction being in the range of from 30 to 50 degrees at the outer main groove, and gradually decreasing therefrom in the first and second curved portions, and being substantially zero in the straight portion.
a depth of each lug groove being smaller in the straight portion than the first curved portion.